In our phytochemical studies of Citrus plants (Rutaceae), we have isolated many kinds of coumarins, acridone alkaloids, and flavanones. In particular, many acridone-coumarin dimers, named acrimarines, which are constructed from various acridone alkaloids and suberosin as a coumarin unit, are characteristic constituents. We recently reported the isolation and structural elucidation of two novel type acridone-coumarin dimers, named neoacrimarines-A and -B, which contain coumarin units other than suberosin. In further investigations of the constituents of Citrus plants, we isolated two novel neoacrimarines, namely neoacrimarine-C(1) and neoacrimarine-D(2), from the root of Citrus hassaku HORT. ex. TANAKA. Their structures were elucidated on the basis of spectroscopic data including high-resolution fast atom bombardment mass spectrum, 1H- and 13C-NMR, UV, IR, 1H-1H correlation spectroscopy, 1H-13C COSY, heteronuclear multiple-bond connectivity spectroscopy, nuclear Overhauser effect experiments, and chemical derivatization (preparation of mono-methyl ether with diazomethane and diacetate with acetic anhydride–pyridine). Neoacrimarine-C (1) is a dimer of citracridone-III and khellactone with an ether linkage between C-5 of the acridone moiety and C-11' of the coumarin moiety, and its relative stereochemistry of the hydroxyl group (C-10) and ether linkage (C-11') was determined to be cis. Neoacrimarine-D (2) has a linkage between C-2 of the acridone moiety and C-11' of the coumarin moiety, with the linear orientation of the 2,2-dimethylpyran ring in the coumarin moiety established by HMBC experiment.